Display device and method of driving the same based on previous frame load

Abstract

A display device includes: a display panel including pixels emitting light, based on a data voltage; a current limiter for determining a scale factor by comparing a previous frame load with a predetermined threshold load, and generating compensated image data by applying the scale factor to current image data as input image data of a current frame to adjust the data voltage; and a data driver for converting the compensated image data into the data voltage and providing the data voltage to the display panel.

What is claimed is: 
     
       1. A display device comprising:
 a display panel including pixels configured to emit light based on a data voltage; 
 a current limiter configured to determine a scale factor by comparing a previous frame load with a predetermined threshold load, and generate compensated image data by applying the scale factor to current image data as input image data of a current frame to adjust the data voltage; and 
 a data driver configured to convert the compensated image data into the data voltage and provide the data voltage to the display panel. 
 
     
     
       2. The display device of  claim 1 , wherein, when the previous frame load is smaller than the threshold load, and a current frame load is greater than the threshold load, a scale factor of the current frame is smaller than that of a previous frame. 
     
     
       3. The display device of  claim 1 , wherein the current limiter generates a time weight, based on the previous frame load and a frame lapse time, and further applies the time weight to the scale factor. 
     
     
       4. The display device of  claim 3 , wherein the scale factor and the time weight are greater than 0 and are equal to or smaller than 1. 
     
     
       5. The display device of  claim 3 , wherein, when a frame load of a first frame is equal to or smaller than the threshold load, and frame loads of second to kth (k is an integer greater than 2) frames are greater than the threshold load, a magnitude of a data voltage corresponding to the same grayscale is gradually decreased as approaching the kth frame from the second frame. 
     
     
       6. The display device of  claim 5 , wherein the scale factor to which the time weight is applied is gradually decreased as approaching the kth frame from the second frame. 
     
     
       7. The display device of  claim 1 , wherein the current limiter comprises:
 a load calculator configured to calculate the previous frame load, based on input image data of a previous frame; 
 a signal controller configured to compare the previous frame load with the threshold load, and output a first control signal, based on a comparison result; and 
 a scale factor adjustor configured to adjust the scale factor, based on the previous frame load and the first control signal. 
 
     
     
       8. The display device of  claim 7 , wherein, when the previous frame load is smaller than the threshold load, the signal controller activates the first control signal, and
 wherein the scale factor adjustor generates a current scale factor by applying a compensation coefficient to a load scale factor corresponding to the previous frame load in response to the first control signal. 
 
     
     
       9. The display device of  claim 8 , wherein, when the previous frame load is equal to or greater than the threshold load, the signal controller inactivates the first control signal, and
 wherein the scale factor adjustor outputs, as the current scale factor, a previous scale factor output in the previous frame. 
 
     
     
       10. The display device of  claim 9 , wherein, when the previous frame load is smaller than the threshold load, the signal controller further outputs a second control signal activated during a buffer period including a plurality of frames. 
     
     
       11. The display device of  claim 10 , wherein the current limiter further comprises:
 a counter configured to output a count value by counting frames of the buffer period; 
 a weight generator configured to generate a time weight which varies in the buffer period in response to the second control signal and the count value; and 
 a calculator configured to apply the time weight to the current scale factor. 
 
     
     
       12. The display device of  claim 11 , wherein the current limiter further comprises:
 a resetter configured to output a count reset signal when both the first control signal and the second control signal are activated, and 
 wherein the counter resets the count value in response to the count reset signal. 
 
     
     
       13. The display device of  claim 12 , wherein the weight generator outputs a first time weight corresponding to a first frame of the buffer period in response to the count reset signal. 
     
     
       14. The display device of  claim 7 , wherein the signal controller comprises:
 a lookup table including a load scale factor corresponding to the previous frame load; and 
 a comparator configured to output a second control signal for controlling generation of the first control signal and the time weight by comparing the previous frame load with the threshold load. 
 
     
     
       15. The display device of  claim 11 , wherein the current limiter generates the compensated image data by applying, to the current image data, the current scale factor to which the time weight is applied. 
     
     
       16. A method of driving a display device, the method comprising:
 comparing a previous frame load with a predetermined threshold load; 
 activating a first control signal and a second control signal, when the previous frame load is smaller than the threshold load; 
 generating a first scale factor by applying a compensation coefficient to a load scale factor corresponding to the previous frame load, based on the first control signal; 
 generating a time weight, based on the activation of the second control signal; 
 outputting a current scale factor by applying the time weight to the first scale factor; and 
 providing a data voltage to a display panel by applying the current scale factor to current image data. 
 
     
     
       17. The method of  claim 16 , wherein the second control signal is activated during a buffer period including a plurality of frames. 
     
     
       18. The method of  claim 17 , further comprising:
 inactivating the first control signal, when the previous frame load is equal to or greater than the threshold load; 
 generating the time weight, based on the second control signal; 
 outputting the current scale factor by applying the time weight to a scale factor output in a previous frame; and 
 providing a data voltage to the display panel by applying the current scale factor to current image data. 
 
     
     
       19. The method of  claim 18 , wherein the time weight is determined by counting frames of the buffer period. 
     
     
       20. The method of  claim 16 , wherein, when the previous frame load is smaller than the threshold load, and a current frame load is greater than the threshold load, a scale factor of the current frame is smaller than that of a previous frame.